The proposed work will develop nanoscale tools for characterizing the mammalian cell;it will ultimately lead to new tools for drug discovery, diagnosis of disease, and studying fundamental cell biology. Its justification is that study of biological entities fundamentally involves the study of nanoscale components of the cell: subcellular organelles, pathogens, macromolecules. Nanoscale tools are required to examine and analyze these components at the subcellular scale. The research will create nanometer-scale components (rods, particles, and surfaces) using "biology-friendly" nanotechnology (soft lithography and self-assembled monolayers), and use them to examine mammalian cells. It will use nanoscience-based approaches to:1) create 2D and 3D microenvironments with controlled shapes, molecular composition, and mechanical characteristics for studies of cells;2) create electrically, optically, and mechanically functional nanosystems that permit selective stimulation of cells, and allow read-out of cellular electrical, chemical and mechanical responses with subcellular resolution;3) leverage systems that exhibit quantum phenomena unique to nanosystems (e.g., superparamagnetism, superluminosity) to generate new physics and chemistry relevant to biology, and use this understanding of physical science to afford fundamentally new classes of information about cell structure and function;4) develop methods to multiplex nanoscale technologies to measure functions and characteristics of single cells in parallel, with high statistical reliability;5) demonstrate the relevance and application of these tools using important biological problems. The work will combine to generate a "nanotool cellular workbench";it has four specific aims: 1) To create novel multifunctional nanometer-scale structures, particles, components, and surfaces, and analytical systems that use these entities, 2) To use this "work bench" of nanotools to understand how individual cells sense mechanical cues and integrate them with chemical and electrical signals in 2D and 3D microenvironments, 3) To create nanoscale control interfaces that rapidly actuate changes in cellular signal transduction and read-out biochemical responses, and 4) To combine these nanotechnologies with microfluidic systems to create prototypes for integrated cellular biochip-based medical devices.